1. Field of the Invention
The invention relates to a substrate and a testing method thereof, particularly to a substrate of electrically connecting testing pads and a testing method thereof.
2. Description of the Related Art
FIG. 1 shows a conventional testing method for a substrate. Firstly, a substrate 10 is provided. The substrate 10 has a first surface 101 and a second surface 102. The first surface 101 is a chip side for attaching a chip, and the second surface 102 is a solder ball side. The first surface 101 has a plurality of first testing pads 103 and the second surface 102 has a plurality of second testing pads 104. The size of the first testing pad 103 is usually smaller than that of the second testing pad 104. The first testing pads 103 electrically connect to the second testing pads 104 to form a plurality of circuits 105. A testing fixture 11 is used for testing the substrate 10. The testing fixture 11 has a first testing probe unit 12 and a plurality of second testing probe unit 13. The first testing probe unit 12 has two first testing probes 121, 122, and each second testing probe unit 13 has two second testing probes 131, 132. The first testing probe unit 12 electrically connects to the first testing pad 103, and each second testing probe unit 13 electrically connects to the second testing pad 104.
In the conventional testing method, the first testing pads 103 must be tested one by one, and the first testing probes 121, 122 must contact with the same first testing pad 103. However, the size of the first testing pad 103 is very small, especially for four-wire test probe, so that it is difficult to dispose the first testing probes 121, 122 on the same first testing pad 103. Therefore, some of the first testing pads 103 may be missed for testing, and it will takes very long time to test the substrate 10.
Consequently, there is an existing need for providing a substrate and a testing method thereof to solve the above-mentioned problems.